Engine.



R. c. HOFFMANf ENGINE.

APPLICATION FILED MAY 6, 1907.

Patented Dec. 8, 1908.

' To all whom it may concern:

UNITED STATES PATENT OFFICE;

' aosco'r. c. norms, 0F ABGOS, iNDIANA.

ENGINE.

Patented Dec, 8, 1908.

Application man 6, 1907. Serial No. 372,212.

Be it known that I, RosooE C. HOFFMAN, a citizen of the United States, residing at Argos, in the county of Marshall and State of Indiana, have invented a new and useful Improvement in Engines, of which the followmg is a specification.

My invention relates particularly to' internal combustion engines; and my primary object is to provide an engine of this character of exceedingly simple construction, in which the vibration and strain are'reduced to a minimum, the use of valve-gear and stufl Figure 1 is a'vertical sectional elevation of my im roved e inc, and Fig. 2 a plan section ta en at the inc 2 on Fig. 1. i

In the construction illustrated, A represents an engine cylinder, surmount-mg a crank -casing B, and within the cylinder works a pair of telescopically-arranged pistons A A A crank-shaft B is journaled -in the casing B, and is provided with a pair of cranks B oined by connecting-rods B to the adjacent end of the cylindrical-piston A, and a crank B joined by a connecting rod B to the inner iston A.

The cylin er A comprises an inner cylindrical wall a and an outer wall a, forming a water-jacket as is common in gas-engine construction. The cylindrical piston A is a relatively lon piston andlaas an open end turned towar the crank-shaft and extending'normally into the casing B where it is equipped with a ring a provided with wristins to which the connecting rods B are oined. Between the outer end' of the cylinder and the adjacent end of the cylindricaliston A is a chamber a rovided with an lnlet-port a, near the hea of the cylinder, and near the opposite, or open, end of the cylinder, is a similar inletort a, in a1ine ment with the port a, and iametrically opposite the port a, is arrrangedan exhaustport a; both the. ports a and a" extend through the inner and outer walls a and a res ectively of the cylinder.

lsear thehead, or outer end of the piston A is a slot 0 adapted to register, in the reciprocations of the piston, with the spark-plug '0 which extends through the cylinder at a boss 0 which joins the two walls a, a of-the cylinder at this point. The cylindrical piston A is provided with an inlet-port c and an exhaust-port 0; adapted to register with the ports a, and a, respectively when the piston is in the position shown in Fig. 1 of the drawing.

An inletipe :1 provided with a branch pipe d and aving its up er end turned at a right-angle as shown at is secured to the cylinder so that its end d and branch d will register with the ports a and a respectively,

. and within the inlet pipe, at a 'omt below the branch-pipe d is arrange a checkvalve (i i The piston A is providedwith a deflector (1 adapted to direct the explosive mixture toward the outer end of the cylindrical piston A and to prevent the incoming mixture from passing directly to the exhaust-port c.

The operation will be readily understood from the foregoingdescription. VVhen the crank-shaft is turned throu h one-half revolution from the position shown in outer end of the cylindrical piston 1 sucks a charge through the valve (1 and port a into the chamber a within the cylinder. When the crank-shaft continuing its revolution, again separates the pistons, the outer end of the cyhndrical, piston .A compresses the charge inthe chamber a until the port 0 of this piston registers with the intake port a when the charge enters the cylindrical pis- 1, the

ton. During the next half revolution of the crank-shaft, the charge is pressed between the pistons, and an instantthereafter 1t 1s fired, theslot 0 being at this time in registra tion with the spark-plug c Thereupon the istons are forced apart, the inner piston orcing the crank-shaft in one direction and the sleeveiston drawing the crank-shaft in the other irection. During the final operation of the separation of the pistons, the port gases which still remain wlthin the. cylindrical piston taken place.-"

The foregoing detailed description has been given for clearness of understanding only, and no unduelimitation'is to be understood therefrom."

What I regard as new and desire to secure by Letters Patent, is-

1. In an engine, the combination of a cyl inder having one end open andthe other after the exhaust proper has closed, said 0 linder having a lateral surface provided wit two admission ports, one of said ports being located adjacent the closed end of the cylinder andjthe other between the first port and the open endof thec lin-. der, a valved inlet pi 0 connected to oth. said ports, thevalve eing located in front of the point of connection with either port, a pair of telescopicapistons, one of which is holow and provlde with an unobstructed lateral admission port which passes transversely through a lateral. wall of the sameand o ens into the interior of the hollow pishereby serving to admit the charge di-iton, t rectly between the pistons, means for exhausting the used char e from between the pistons,-and' a crank-s aft connected with said istons.

2. 11 an engine, the combination of a cy 'linder having one end open and the other closed, said 0 linder having a lateralsurace provided wit two admisslon ports,'-"; o[ne ofsaid ports being located'adjacentthe closed end'of the cylinder and the other between the first port and the open end of the c linder, avalved inlet pipe connected to both said ports, the valve eing located in front of the-point of connection with either port,

a air of telescopicistons, one of which is ho low and rovide with an unobstructed lateral admission-port which passes transversely through a lateral wall of the same and (Eons into the interior of the hollow piston, ereby serving to admit the charge directly between the pistons, said cylinder being also provided with an exhaust port located opposite the admission port which is more remote from the closed end of the cylinder, said hollow piston being provided with an exhaust port in line with the admission port, a deflector carried by the head of the other piston, and a crank shaft connected with both said pistons. 1

3. In an engine, the combination of a cylinder having one end open and the other closed,' said 0 linder havmg a lateral surface provided wit two admission ports, one of said ports being located adjacent the closed end of the cylinder and the other between the first port and the open end of the c linder, a va ved inlet pi e connected to said ports, the valve eingjlocatedin front of the oint of connection with either ort, a.

air 0 telescopic-pistons, one of w 'ch is.

i pistons.

ROSCOE. o. HOFFMAN.

, In the presence of v Gnonen O. R ED,

EUGENE E. WILLSEY. 

